tests: check liquidity hints are updated for all htlcs

diff --git a/tests/test_lnpeer.py b/tests/test_lnpeer.py
index 19e0231..d4d0204 100644
--- a/tests/test_lnpeer.py
+++ b/tests/test_lnpeer.py
@@ -2250,6 +2250,23 @@ class TestPeerForwarding(TestPeer):
         with self.assertRaises(PaymentDone):
             await f()
 
+    async def _assert_no_inflight_htlcs_in_liquidity_hints(self, w: MockLNWallet):
+        # pay_invoice returns when the first htlc resolution is processed; the remaining
+        # parts resolve later. only when all parts have resolved is the paysession removed.
+        async def wait_for_paysessions_to_be_cleaned_up():
+            while w._paysessions:
+                await asyncio.sleep(0.01)
+        await util.wait_for2(wait_for_paysessions_to_be_cleaned_up(), timeout=10)
+        for hint in w.network.path_finder.liquidity_hints._liquidity_hints.values():
+            self.assertEqual(0, hint.num_inflight_htlcs(True))
+            self.assertEqual(0, hint.num_inflight_htlcs(False))
+
+    def _assert_all_parts_reported_can_send(self, w: MockLNWallet):
+        # every part of the mpp resolved successfully, so every edge an htlc was
+        # sent over should have received a can_send report for its direction of use
+        for hint in w.network.path_finder.liquidity_hints._liquidity_hints.values():
+            self.assertTrue(hint.can_send(True) is not None or hint.can_send(False) is not None)
+
     async def _run_mpp(self, graph, kwargs):
         """Tests a multipart payment scenario for failing and successful cases."""
         self.assertEqual(500_000_000_000, graph.channels[('alice', 'bob')][0].balance(LOCAL))
@@ -2299,8 +2316,11 @@ class TestPeerForwarding(TestPeer):
                         await g.spawn(peer.wait_one_htlc_switch_iteration())
                 for peer in peers:
                     self.assertEqual(len(peer.lnworker.received_mpp_htlcs), 0)
+                await self._assert_no_inflight_htlcs_in_liquidity_hints(alice_w)
+                self._assert_all_parts_reported_can_send(alice_w)
                 raise PaymentDone()
             elif len(log) == 1 and log[0].failure_msg.code == OnionFailureCode.MPP_TIMEOUT:
+                await self._assert_no_inflight_htlcs_in_liquidity_hints(alice_w)
                 raise PaymentTimeout()
             else:
                 raise NoPathFound()
diff --git a/tests/test_lnrouter.py b/tests/test_lnrouter.py
index 3ad775c..bcbe3e5 100644
--- a/tests/test_lnrouter.py
+++ b/tests/test_lnrouter.py
@@ -373,6 +373,19 @@ class Test_LNRouter(ElectrumTestCase):
         # we have got 600 (attempt) + 600 (inflight) penalty
         self.assertEqual(1200, liquidity_hints.penalty(node_from, node_to, channel_id, 1_000_000))
 
+    def test_reset_liquidity_hints_clears_inflight_htlcs(self):
+        liquidity_hints = LiquidityHintMgr()
+        node_from, node_to = bytes(0), bytes(1)
+        channel_id = ShortChannelID.from_components(0, 0, 0)
+        liquidity_hints.add_htlc(node_from, node_to, channel_id)
+        liquidity_hints.add_htlc(node_to, node_from, channel_id)
+        hint = liquidity_hints.get_hint(channel_id)
+        self.assertEqual(1, hint.num_inflight_htlcs(node_from < node_to))
+        self.assertEqual(1, hint.num_inflight_htlcs(node_to < node_from))
+        liquidity_hints.reset_liquidity_hints()
+        self.assertEqual(0, hint.num_inflight_htlcs(node_from < node_to))
+        self.assertEqual(0, hint.num_inflight_htlcs(node_to < node_from))
+
     @needs_test_with_all_chacha20_implementations
     def test_new_onion_packet(self):
         # test vector from bolt-04